Painting outside metal door
About a year ago, I had my front entrance (metal door w/frame and sidelights) replaced by a big-box store. It came with primer applied. The primer coat seemed rather light (thin); not like other primers I have used.
I had the unit professionally painted. He used 5 coats of a latex-based Rustoleum paint (I purchased it; he approved)to properly cover the primer.
Shortly thereafter, noticed some small chips around the locksets. Within a few months, I noticed that the paint was forming bubbles which were separating from the door, and has gotten progressively worse through the winter.
I notice that the (original) primer is still visible where the paint has pulled away--like the paint never 'bonded' with the primer.
I want to remove the paint, with a heat gun, apply new primer over the original primer, then top coat with sufficient paint to cover.
As mentioned, this is a metal door. Of interest, the sidelights (same primer) was painted with latex paint and has held up just fine.
I'm looking for recommendations for primer and paint. Also, any tips regarding removal of old paint and applying new paint.